"Fashion Star" has whittled the contestants down to a small group of designers, and now, it's time to shake up the weekly runway format. For this week's challenge (Tues., May 1, 10 p.m. ET on NBC), the remaining designers are focusing on their personal brands and creating campaigns for their collections.

The mentors -- Nicole Richie, Jessica Simpson and John Varvatos -- will give the designers guidance and insight into what makes a successful campaign. Not all of the designers take the advice, though ...

We've got two exclusive sneak peeks at the upcoming episode, "What's Your Campaign?," one of which features Richie's take on this particular challenge and her designer mentee, Nzimiro, the recipient of her cutest nicknames.

"A campaign is a real game-changer," Richie says. "This is the designers' opportunity to stop people dead in their tracks when they're walking down the street, and I'm not sure if Nzimiro's headed in the right direction."

But it appears she's gotten through to Nzimiro with her opinions about sweaters, leaving him with the final parting words of "one love" and an awesome handshake -- just two more reasons to love her mentoring style.

The other clip gives us a revealing look at the judging. Who does Jessica Simpson say really "knocked my panties off"? And who did John Varvatos bow down to? Watch our two exclusive sneak peeks of this week's ad campaign challenge to see.